Under-reamer.



N0. 634,94l. Patented Oct. l7, I899.

M HALL UNDER REAMER.

(Application filed Feb. 28, 1898.)

(No Model.)

forming part of my invention.

llwirnn drains PATENT rricn.

MAJOR HALL, OF BOISE, IDAHO, ASSIGNOR' OF TIVO 1THIRDS TO JAMES M. HERBERT AND RICHARD B. PLOWMAN, OF SAME PLACE.

UNDER-REAMER.

SPECIFICATION forming part of Letters Patent No. 634,9d1, dated October 17, 1899.

Application filed February 26, 1898. Serial No. 671,722. No model.)

To all whom it may concern:

Be it known that I, MAJOR HALL, of Boise, Ada county, Idaho, have invented certain Improvements in Under-Reamers, of which the following is a specification.

My invention relates to improvements in that class of well-drilling tools designed to ream or enlarge the well, my object being to provide a device which may be passed down through a string of casing in the well, and which will expand and be strong enough to ream or enlarge the hole below the casing sufficiently for the casing to follow, and which can be withdrawn without danger of its becoming fastened in the well.

To t his end my invention consists in the novel features of construction hereinafter particularly described and claimed.

In the accompanying drawings, forming part of this specificatiomFigure 1 is a view of my device shown positioned in the well-. casing, said casing being shown in section. Fig. 2 is a longitudinal section of my invention, taken through the cuttersf Fig. 3 is a side elevation looking toward the cutters, and Fig. 4L is a detail of one of the block-cutters.

My invention consists of a preferably cylindrical body A, having its upper end 2 screw- .threaded to be fastened in the usual manner to the stem above. 13 represents the cutters These are solid block-cutters (see detail Fig. 4:) arranged in side openings 3 in the lower end of the tool.

The inner ends of said block-cutters stand when expanded, as will be seen, in line with the center of the tool, abutting against the central boss 4. A pin or cylindrical block 5 is secured intermediate of the cutters to serve as a central bearing, upon which said cutters oscillate. Said cutters are adapted to be carried and held in outturned or cutting position by means of the rods 6, connecting them with the coil-springs 7, arranged in openings 8 in the opposite sides of the tool, said openings being preferably covered by the protecting-collar 9. By reference to the drawings it will be seen that when the cutters stand in outturned or cutting position their upper ends will abut against the adjacent wall or body of the tool, which serves as a solid backing to resist the thrust and strain of the cutters.

It will be seen that the angle assumed by the cutters when in outturned position is such that the pinch or pressure caused by the impact of the cutters againstthe wall tends directly inward to offset and minimize the lever age, and as the body portion of the tool serves as a solid back wall for the cutters it will be evident that great strength is obtained.

In order to-break up the chips and cuttings removed from the wall by the cutters I provide the tool with a central downward extension 11, having its end 12 tapered to consti+ tute a cutting-point;

My invention is especially adapted for use in territory where in the process of sinking alternate strata of hard and soft or caving formations have to be gone through and where it is necessary to case out material falling into the well or Where for any reason it may become desirable after the casing has been inserted in the well to continue the casing to a greater depth.

In operation the tool is fastened in the usual manner to the stem above and the cutters pressed inward against the tension of their controlling-springs 7, so as to allow the-tool to be passed downward in the casing. The tool is then passed down through the casing until the bottom of the same is reached, when the cutters will spring outin position to work. The tool is then operated in the ordinary manner to cause the cutters to ream out the wall of the well sufficiently to allow the casing to' follow. hen the tool is withdrawn,the cutters will automatically close at the bottom of the casing sufficiently to allow it to pass up Without danger of becoming fastened in the well.

' To remove the cutters for the purpose of sharpening, it is only necessary to take out the center pin 5, when they vcan be drawn downward and unhooked from the springcontrolled rods 6.

Having thus described the construction of my invention ,and the method of, its use, I claim 1. A tool of the class described, comprising in combination a body portion, block-cutters having pivotal support therein, means for turning said cutters outward at an angle with the center line of said tool, and an interposed fixed head-block against which the cuttersv tween the cutters serving' as a bearing upon which they turn, and a fixed head-block arranged betweenthe inner ends of the cutters above said bearing-pin, and means for turning said cutters outward with their inner ends abutting against said head-block.

In testimony whereof I affiX my signature in presence of two witnesses.

MAJOR HALL.

lVitnesses:

HARRY O. WYMAN, EARL C. MAUPIN. 

